1. Field of the Invention
This invention relates to security systems.
2. Description of the Prior Art
It is known to use recorded audio-video material (AV) as evidence in a legal proceeding, such as a criminal prosecution. This recorded AV could be, for example, AV recorded by closed-circuit-television (CCTV) cameras located within the premises of a shop, the recorded AV being used as evidence of a theft of goods from the shop. As another example, digital AV cameras may be used to record the activities occurring in the centre of a town or city, the recorded AV being used as evidence of the occurrence of a crime.
However, there is always the danger that the recorded AV could be tampered with or modified. Even if it is not tampered with, the fact that this is possible means that the validity of the AV data can be challenged. There is also the danger that the AV recording systems themselves are tampered with, for example by a criminal who does not wish his actions to be successfully captured by a camera.
It is important, during a legal proceeding, to be satisfied of the authenticity and integrity of any recorded AV that has been submitted as evidence Otherwise, decisions based on recorded AV, the authenticity or integrity of which is in doubt, may be unsound.
This invention provides a media data security system for rendering a secure media data file, having associated authentication data, for output, the system comprising:
a data preparation unit operable with respect to a version of the media data file, having user controls for generating a list of desired render operations to be applied to the media data file; and
a secure data reproducer arranged to receive the list of desired render operations from the data preparation unit and to render the secure media data file for output on the basis of the list of render operations, the secure data reproducer comprising:                a data authenticator for detecting the authenticity of the secure media data file using the authentication data; and        a data reproducer operable, if the data authenticator detects that the input data is authentic, to perform the list of desired render operations with respect to the secure media data file.        